The site of action potential generation in unipolar snail neurons was identified by stimulating neurons isolated together with the initial portion of the process from the neuropile. Stimulation consisted of a sinusoidal from electrical current passed along the soma-axonal axis in saline solution. No low threshold sites of action potential generation were found in 80% of test neurons using this technique. Spontaneous activity was determined by the operation of one dominant site on the neuronal process. Antidromic activation of the soma by axonal action potentials (even with simultaneous hyperpolarization of the soma) induced somatic potentials more successfully than direct somatic depolarization by the current flowing through the solution.